Conventionally, a thread portion and other portions of a metallic part which are required to be prevented from seizure are generally coated with a lubricant.
Examples of the metallic part include a metallic shell of a gas sensor, which is attached to an exhaust pipe or the like of an internal combustion engine for detecting a specific gas component in an analyte gas, and a tightening nut of a temperature sensor, which is attached to an exhaust pipe or the like for measuring the temperature of an analyte gas.
An example of the lubricant which has been proposed is a paste-like lubricant formed of a lube base oil or the like and a solid lubricant added to the base (see, for example, Patent Documents 1 and 2).